Siemens sirius soft starter 3rw3 and 3rw4 series siemens 3rw3016 1bb14 the siemens 3rw3016 1bb14 is a sirius soft starter from the 3rw30 range this starter is used to start three phase induction motors with reduced torque and reduced starting currentthe starter has been developed to enable the soft run up and slow down of dc motors it helps the mechanical power transmitting elements of the machine at the start by reducing the starting torque and efficiently protects the network from dange